This invention concerns lifting hooks and more particularly lifting hooks for rubbish containers which are engaged by a powered pickup bar to be hoisted and inverted to dump the contents into a collection truck.
Trash collection in many large cities is now highly mechanized to reduce the labor costs and improve the efficiency of the process. Such mechanization involves a powered lifting of the container by a lifting device controlled from within the collection truck by the driver. The lifting device has included pairs of lifting hooks fixed on either end of the containers engaged by a pickup bar as the device is actuated to move the bars towards the hooks and upwardly, with the container then hoisted and partially inverted to dump its contents into the truck. The driver does not dismount from the truck so that a single worker can quickly handle each pickup.
It sometimes happens that in the jostling that occurs in the container's movement away from the partially inverted position, the hooks unseat from the pickup bar and the container is dropped from its elevated position, presenting a hazard and damaging the container itself.
While it is well known to utilize locking accessories on lifting hooks, these have therefor required manual manipulation of the locking elements in securing and releasing the device. Inclusion of these devices would require dismounting by the driver, so that efficiency of the operation would be greatly reduced, or the driver would simply neglect to use the device.
Any such safety device should not make engagement of the pickup bars with the hook more difficult so as to make the operation more difficult or time consuming.
Also, any such devices must be very rugged and dependable to withstand the rough handling inherent in these operations.
Accordingly, it is an object of the present invention to provide a catch device for reducing the incidence of dislodgement of pickup bars from lifting hooks for containers which does not necessitate any separate activating steps, and which is rugged and dependable to operate reliably in this environment.